Thanks for the response!
It is the version:
"2006/02/06 MASTER VER."
The reset is also when you only press credit and one other button.
I have a normal 4 button + credit + start button supergun setup.
Anyway got this response from sophia:
1)NO ENEMY ON THE 3RD STAGE
IT?S DIFFICULT TO UNDERSTAND REASON.
HOWEVER, CAVE SAID THAT IT SEEMS AN ERROR OF READING HAPPENED AT THAT TIME.
WOULD YOU PLEASE SEND IT BACK TO US ONCE?
WE WANT TO SEND IT TO CAVE IF YOU COULD ACCEPT.
2)RESET
CAVE SAYS IT IS NORMAL SPECIFICATION.
THIS PCB IS FOR BUSINESS USE.
IN ORDINARY CASES, NO BODY PUSH COIN SWITCH TOGETHER WITH OTHER BUTTONS IN GAME CENTERS.